This invention relates to an assembly for driving and supporting a wheel hub on a wheel carrier of a motor vehicle.
The invention relates to an assembly for driving and supporting a wheel of a motor vehicle, which comprises a wheel hub, a constant velocity joint and means for supporting the assembly on the wheel carrier of the motor vehicle. The wheel hub is associated with a flange for fixing the wheel. The constant velocity joint is fixed to the wheel hub for transmitting torque. The wheel hub is rotatably supported around a common longitudinal axis of a rolling contact bearing comprising two rows of rolling contact members supported by an outer bearing ring at the wheel carrier. The two rows of rolling contact members are tensioned relative to one another in the direction of the longitudinal axis. An outer joint member secures the constant velocity joint to the wheel hub in a direction or rotation around the longitudinal axis by two inter-engaging sets of teeth. The outer joint member is secured along the longitudinal axis. Further, the rolling contact members are guided for rolling on axially spaced outer tracks of the outer bearing ring facing away from one another and on inner tracks facing one another. The first teeth set is arranged at the end, removed from the flange, and behind the bearing face, to receive the separate inner bearing ring. The first set of teeth comprises teeth extending parallel to the longitudinal axis.
Such an assembly is described in EP 0 610 782 A1 wherein the separate inner bearing ring is form-fittingly secured to the wheel hub. In the region adjoining the seat face for the inner bearing ring, the wheel hub comprises a set of teeth. The outer joint member of the connected constant velocity joint comprises a bore. Teeth are worked into the bore. The teeth of the outer joint member interlock with the teeth of the wheel hub. The outer joint member is axially secured to the wheel hub by a securing ring.
U.S. Pat. No. 4,986,607 describes a wheel bearing assembly wherein a first inner face is worked into a wheel hub near a flange. The outer joint member of a constant velocity joint comprises a second inner face and a journal which projects towards the flange of the wheel hub and extends into a bore in the wheel hub towards the flange. Underneath the flange, the wheel hub in its bore, comprises a bore part which increases conically in size away from the outer bearing ring and constant velocity joint. The wheel hub includes a set of hardened teeth which also expands conically in this bore part. After the outer joint member is fitted into the wheel hub, the journal end is plastically deformed such that material is displaced outwardly and reaches the empty spaces between the hardened teeth of the wheel hub. As a result, the outer joint member is fixed relative to the wheel hub, in both the axial direction and the direction of rotation around the longitudinal axis.
The disadvantage of such an arrangement and assembly method is that relatively high deformation forces are necessary to cause the material to flow into the gaps between the teeth. A further disadvantage is that the wheel hub has to be subjected to high radial forces. Further, it is essential to provide a relatively solid assembly, i.e. the assembly is relatively heavy because it needs a solid journal at the outer joint member of the constant velocity joint. Furthermore, it is necessary for the outer joint member to be produced from a relatively expensive material because it comprises an inner track, i.e. it has to be made of a rolling contact bearing steel, whereas traditionally, constant velocity joints are made of a relatively reasonably priced induction-hardenable or case-hardenable steel.
The known embodiments are also deficient in that relatively high axial deformation forces are generated when fixing the outer joint member relative to the wheel hub. There is a risk that the necessary pretension in the rolling contact bearing will not be observed with the required degree of accuracy.
DE 36 36 243 A1 describes a non-rotating connection between the inner bearing ring and the wheel hub of a wheel bearing constant velocity joint unit, wherein the inner bearing ring, prior to assembly, includes teeth. A portion of the wheel hub is a collar formed by coining to form-fit a connection between two parts. The inner ring includes teeth to be connected to teeth of the outer joint part of the constant velocity joint.